Automobile body repair often requires that the damaged area be filled with a body repair compound. The filling compound can be a glass bubble filled polyester resin that is mixed with a peroxide to facilitate cross-linking at room temperature. After mixing, the technician uses a squeegee to spread the repair compound onto the surface of the vehicle to roughly match the contour of the surface. The technician uses an abrasive article to form and shape the body repair material to more closely match the contours of the original body. This process can be repeated two or more times until the damaged area of the vehicle is sufficiently filled and the contour of the original body is matched.
One problem associated with this process is the creation of pinholes within the contoured body repair compound. Pinholes can come from several sources. One source is air that is trapped when the polymer is mixed with the catalyst or when the mixture is spread onto the substrate using a device like a squeegee. As the material is folded or spread, air can get trapped into the material. To overcome these pinholes, multiple layers of body repair compound and lower viscosity putties or glazes are applied to fill the pinholes. Even with these precautions, pinholes will still reveal themselves after sanding, priming, and painting are complete. During the priming and painting process, the exposed pinhole may be bridged by primer or paint coatings and not totally filled. Upon application of subsequent layers of paint such as a clearcoat or after baking, the bridged coatings may collapse resulting in a depression in the surface.
Pinholes are a tremendous source of waste in the process of repairing damaged substrates. Pinholes require multiple layers of putty or filler be applied over the first body repair compound layer to fill the pinholes. Multiple coats of prime layers are required to cover the pinholes. Each application of putty layer or prime layer requires 10 to 20 minutes to complete. Thus, elimination or reduction in the added time and expense of pinholes within the contoured body repair compound is desired.